I have Audacity 2.0.5 on Windows 7 64 bit.
I have a Lambda Lexicon USP device that send the sound to my self powered speakers. I can also plug my guitar into the Lamda for recording.
I imported an MP3 backing track, which sounds very good on playback, and I can record the guitar along with the backing track.
Problem: the backing track volume is higher than the guitar, and I do not know how to control the backing track volume during recording.